Jim is right. If you want to gain strength your going to have to eat! A little before and a lot after you workout. If your trying to "cut", i am assuming you mean have less body fat, 5/3/1 is probably not a good program for you. I am sure people maybe cut but 5/3/1 is a program for raw strength not have chiseled abs. And if your going to do BBB you have to eat A LOT!
Everybody has different goals as to what they want like to be huge, ripped, be as strong as they can get etc. You just need to figure out what you want and go from there.